Objective: Diagnostic test results are often not interpreted in the context of patients' clinical characteristics. The objective of this research is to improve care of patients presenting to the emergency department (ED) with possible acute cardiac ischemia (ACI) by enhancing the appropriate use and interpretation of results of diagnostic tests to detect ACI. Specific Aims: To create and evaluate an interactive computer-based diagnostic strategy aid for ED physicians that provides estimates of risk of ACI given patient and ECG features, and specific test results. Methods: Data from 5 clinical trials of ED patients presenting with symptoms of ACI will be used to develop and test models for risk of ACI and diagnostic performance. These models will be applied in Bayes' Rule to calculate post-test likelihood of ACI. A computer-based interactive interface will be developed that will show physicians how risk of ACI changes given patient clinical and ECG characteristics and specific test results. We will pilot test the aid in the ED to assess functionality and performance. The ultimate goal is to assess its impact on patient care in a clinical trial.